RE: [hreg] Assistance RESPONSE

Robert, Bass boats aren’t economically feasible for 99% of their owners either, but they are selling them like hotcakes (no offense to any Bass fisherpeople

Message 1 of 11
, Sep 3, 2005

0 Attachment

Robert,

Bass boats aren’t economically
feasible for 99% of their owners either, but they are selling them like
hotcakes (no offense to any Bass fisherpeople out there, but there is a much
cheaper way to get fish).

I don’t think you are missing too
much, except perhaps that most consumers of pv aren’t looking at the
purchase of a system primarily as an investment such as they might stock, real
estate, etc.…… and certainly not in this market of incredibly
inexpensive utility costs. Instead, it is a beneficial, fascinating device that
is for some, a luxury item……. one that happens to have a payback.

However, unlike other luxury items (luxury
automobiles, hot tubs, big-screen TV’s, and bass boats) pv actually does
have a payback, and actually does, from the minute it is exposed to sunlight
and put to work, begin to offset the amount of energy required in its
manufacture.

I think Randy Udall captured the sentiment
quite well in this article:

If I put Bashir’s $6/W cost with Andrews estimate of 4.5kWh system for
$505 worth of annual electrical energy, then that says the system should cost
on the order of $27,000 to install. If it saves $505 in electrical energy
costs, that is a 53 year payback, or twice the expected life of the
equipment. I haven’t made allowance for rising electricity costs,
but neither have I factored in the finance costs of the system (or the
opportunity cost of spending the $27k if one were to tie up that much cash
instead of investing it elsewhere), so isn’t this reasonable for a very
rough calculation? If this is correct, then what Andrew is showing us is
what I’ve always heard—that PV is not yet economically viable
except for remote installations. Am I missing something?

There are many ways of calculating the
“payback” of a pv system………some which make it
look more appealing, some which make it worse, some using very basic
calculations, some using complex financial analyses and calculated energy
projections.

The method however, that has been
presented in this thread, is most peculiar.

First of all, while acceptable to use the
NREL average for back-of-the envelope calculations, it probably isn’t
acceptable to simply de- rate
the STC rating of the array
by the inefficiency of it as there are many other inefficiencies that come into
play by the time the power from the system in question gets put to work.

This pitfall is illuminated in the example
that a 3 kW array will provide the 450 kWh/month (average) or 5400
kWh/year. To be clear: it would not, at least not in
Houston .

Secondly, and regarding the basis for the
calculations we have seen:

It will be very hard to install to
functionality a quality 3 kW system installed for $18K. Furthermore, it
would seem that the example case is assuming a $.56/kWh
rate (5400 kWh/Year for $3K).
Perhaps this includes environmental costs or other “intangibles”,
which is most appropriate in a big-picture way, but maybe not so much for a
bare-bones payback analysis.

I am a pv advocate and I believe that a
true accounting should incorporate all social and environmental costs, in
addition to the financial ones. However, or perhaps because of that
advocacy, I think that a clear representation needs to made as to the
limitations, as well as the capabilities, of this technology with respect to
people’s energy “needs”.

See below for a more “real
world” projection for what the 3 kW system in question might actually do
in Houston :

Station
Identification

City:

Houston

State:

TX

Latitude:

29.98° N

Longitude:

95.37° W

Elevation:

33 m

PV System
Specifications

DC
Rating :

3.0 kW

DC to AC Derate
Factor:

0.770

AC
Rating :

2.3 kW

Array Type:

Fixed Tilt

Array Tilt:

30.0°

Array Azimuth:

180.0°

Energy Specifications

Cost of Electricity:

9.2 ¢/kWh

Results

Month

Solar Radiation
(kWh/m2/day)

AC Energy
(kWh)

Energy Value (estimated)
($)

1

3.68

252

23.18

2

4.12

251

23.09

3

4.82

321

29.53

4

4.98

315

28.98

5

5.24

335

30.82

6

5.53

337

31.00

7

5.43

338

31.10

8

5.44

342

31.46

9

5.40

332

30.54

10

5.19

334

30.73

11

4.33

277

25.48

12

3.34

226

20.79

Year

4.79

3660

336.72

And here for an output projection for the
system one might need (with correct array orientation) to hit their 5400
kWh/year consumption mark:

Station Identification

City:

Houston

State:

TX

Latitude:

29.98° N

Longitude:

95.37° W

Elevation:

33 m

PV System Specifications

DC Rating :

4.5 kW

DC to AC Derate Factor:

0.770

AC Rating :

3.5 kW

Array Type:

Fixed Tilt

Array Tilt:

30.0°

Array Azimuth:

180.0°

Energy Specifications

Cost of Electricity:

9.2 ¢/kWh

Results

Month

Solar Radiation
(kWh/m2/day)

AC Energy
(kWh)

Energy Value (estimated)
($)

1

3.68

377

34.68

2

4.12

376

34.59

3

4.82

481

44.25

4

4.98

472

43.42

5

5.24

502

46.18

6

5.53

505

46.46

7

5.43

508

46.74

8

5.44

514

47.29

9

5.40

498

45.82

10

5.19

500

46.00

11

4.33

416

38.27

12

3.34

339

31.19

Year

4.79

5489

504.99

Andrew H. McCalla

Meridian Energy Systems

2300 S. Lamar,
Ste. 107

Austin,
TX 78704

SBT Designs

Why don t we just stop kidding ourselves? The entire concept of payback from a solar power system is a dinosaur from the 1980s when the government,

Message 2 of 11
, Sep 3, 2005

0 Attachment

Why don't we just stop kidding ourselves? The
entire concept of "payback" from a solar power system is a dinosaur from the
1980s when the government, academics and solar vendors alike were trying to
justify to the American consumer (the most uneducated consumer in the
world) why we should invest in solar. At best this data is a weak
marketing tool.

So called calculations of payback are little more
than fiction because all renewable energy systems are subject to the behavior of
weather. We have been trying to predict the weather for thousands of years
with less than accurate results. Because you cannot tell me what the
weather will be like tomorrow you also cannot tell me how much power a renewable
energy power system will produce. I can offer you any "calculations" you
like for a solar power system for any location in the world. Your
calculations, my calculations and anyone else's calculations would be just
as accurate as gazing into a crystal ball. And your crystal ball works
just as well as mine. Most American consumers don't read and would not
even understand payback calculations and estimates. And let's not even
bring up the topic of efficiencies. When I am asked about efficiency that
is always the first indication of a clueless consumer. The next
indication would be that consumer concerned about the "imbedded pollution" of
the solar manufacturing process. Give me a break. These concerns and
payback concerns are the concerns of a consumer who probably has no intention of
investing in renewable energy - plain and simple.

The basic practical fact of investing in solar
technology (or any renewable energy technology) is that a solar power system is
an on site electric power generator capable of providing power if no utility
power is available at all, capable of providing electricity in the event of
utility failure and/or capable of producing distributed power that can be
applied back to the grid at large. The fuel for that generator is free,
natural, nonpolluting sunshine. If the American consumer cannot
recognize the logic and practical nature of this basic fact (and they
don't) why waste time producing pages of nearly useless data that
will end up in the trash can? And what about the risk that some grubby
lawyer might use that data against you in the future because your solar
power system did not deliver as predicted by your payback
estimates?

There are many ways
of calculating the payback of a pv system some which make it look more
appealing, some which make it worse, some using very basic calculations, some
using complex financial analyses and calculated energy
projections.

The method however,
that has been presented in this thread, is most
peculiar.

First of all, while
acceptable to use the NREL average for back-of-the envelope calculations, it
probably isnt acceptable to simply de-rate the STC rating of the array by the
inefficiency of it as there are many other inefficiencies that come into play
by the time the power from the system in question gets put to
work.

This pitfall is
illuminated in the example that a 3 kW array will provide the 450 kWh/month
(average) or 5400 kWh/year. To be clear: it would not, at
least not in
Houston .

Secondly, and
regarding the basis for the calculations we have seen:

It will be very hard
to install to functionality a quality 3 kW system installed for $18K.
Furthermore, it would seem that the example case is assuming a $.56/kWh rate
(5400 kWh/Year for $3K). Perhaps this includes environmental costs or
other intangibles, which is most appropriate in a big-picture way, but maybe
not so much for a bare-bones payback analysis.

I am a pv advocate
and I believe that a true accounting should incorporate all social and
environmental costs, in addition to the financial ones. However, or
perhaps because of that advocacy, I think that a clear representation
needs to made as to the limitations, as well as the capabilities, of this
technology with respect to peoples energy
needs.

See below for a more
real world projection for what the 3 kW system in question might actually do
in
Houston :

Station
Identification

City:

Houston

State:

TX

Latitude:

29.98°
N

Longitude:

95.37°
W

Elevation:

33
m

PV System
Specifications

DC
Rating:

3.0
kW

DC to AC
Derate Factor:

0.770

AC
Rating:

2.3
kW

Array
Type:

Fixed
Tilt

Array
Tilt:

30.0°

Array
Azimuth:

180.0°

Energy
Specifications

Cost of
Electricity:

9.2
¢/kWh

Results

Month

Solar
Radiation(kWh/m2/day)

AC
Energy(kWh)

Energy
Value (estimated)($)

1

3.68

252

23.18

2

4.12

251

23.09

3

4.82

321

29.53

4

4.98

315

28.98

5

5.24

335

30.82

6

5.53

337

31.00

7

5.43

338

31.10

8

5.44

342

31.46

9

5.40

332

30.54

10

5.19

334

30.73

11

4.33

277

25.48

12

3.34

226

20.79

Year

4.79

3660

336.72

And here for an
output projection for the system one might need (with correct array
orientation) to hit their 5400 kWh/year consumption
mark:

Station
Identification

City:

Houston

State:

TX

Latitude:

29.98°
N

Longitude:

95.37°
W

Elevation:

33 m

PV System
Specifications

DC Rating:

4.5 kW

DC to AC Derate
Factor:

0.770

AC Rating:

3.5 kW

Array
Type:

Fixed Tilt

Array
Tilt:

30.0°

Array
Azimuth:

180.0°

Energy
Specifications

Cost of
Electricity:

9.2
¢/kWh

Results

Month

Solar
Radiation(kWh/m2/day)

AC
Energy(kWh)

Energy Value (estimated)($)

1

3.68

377

34.68

2

4.12

376

34.59

3

4.82

481

44.25

4

4.98

472

43.42

5

5.24

502

46.18

J. P. Malone

Thanks for the very direct answer. I agree with your assessment of our education as clueless consumers. I am guilty. I, see from your SBT Systems web site

Message 3 of 11
, Sep 4, 2005

0 Attachment

Thanks for the very direct answer. I agree with your assessment
of our education as clueless consumers.I am guilty.

I, see from your SBT Systems web site that you specialize in installing
solar systems.So it must be a tough
sell when you are basically selling either (1) a backup generator that may be
seldom used, or (2) a luxury toy that only an elite few can truly afford
without being ignorant about their personal capital allocation.

I look forward to the day when a number of the products you sell
will be efficient for average consumers & small businesses to use without
the marketing hype you refer to in your email.

Why don't we just stop kidding ourselves? The entire
concept of "payback" from a solar power system is a dinosaur from the
1980s when the government, academics and solar vendors alike were trying to
justify to the American consumer (the most uneducated consumer in the
world) why we should invest in solar. At best this data is a weak
marketing tool.

So called calculations of payback are little more than
fiction because all renewable energy systems are subject to the behavior of
weather. We have been trying to predict the weather for thousands of
years with less than accurate results. Because you cannot tell me what
the weather will be like tomorrow you also cannot tell me how much power a
renewable energy power system will produce. I can offer you any
"calculations" you like for a solar power system for any location in
the world. Your calculations, my calculations and anyone
else's calculations would be just as accurate as gazing into a crystal
ball. And your crystal ball works just as well as mine. Most
American consumers don't read and would not even understand payback calculations
and estimates. And let's not even bring up the topic of
efficiencies. When I am asked about efficiency that is always the first
indication of a clueless consumer. The next indication would be that
consumer concerned about the "imbedded pollution" of the solar manufacturing
process. Give me a break. These concerns and payback concerns are
the concerns of a consumer who probably has no intention of investing in
renewable energy - plain and simple.

The basic practical fact of investing in solar
technology (or any renewable energy technology) is that a solar power system is
an on site electric power generator capable of providing power if no utility
power is available at all, capable of providing electricity in the event
of utility failure and/or capable of producing distributed power that can be
applied back to the grid at large. The fuel for that generator is free,
natural, nonpolluting sunshine. If the American consumer cannot
recognize the logic and practical nature of this basic fact (and they don't)
why waste time producing pages of nearly useless data that will
end up in the trash can? And what about the risk that some grubby lawyer
might use that data against you in the future because your solar power
system did not deliver as predicted by your payback estimates?

There are many ways of calculating the
“payback” of a pv system………some which make it
look more appealing, some which make it worse, some using very basic
calculations, some using complex financial analyses and calculated energy projections.

The method however, that has been
presented in this thread, is most peculiar.

First of all, while acceptable to use the
NREL average for back-of-the envelope calculations, it probably isn’t
acceptable to simply de-rate the STC rating of the array by the inefficiency of
it as there are many other inefficiencies that come into play by the time the
power from the system in question gets put to work.

This pitfall is illuminated in the example
that a 3 kW array will provide the 450 kWh/month (average) or 5400
kWh/year. To be clear: it would not, at least not in
Houston .

Secondly, and regarding the basis for the
calculations we have seen:

It will be very hard to install to
functionality a quality 3 kW system installed for $18K. Furthermore, it would
seem that the example case is assuming a $.56/kWh rate (5400 kWh/Year for
$3K). Perhaps this includes environmental costs or other
“intangibles”, which is most appropriate in a big-picture way, but
maybe not so much for a bare-bones payback analysis.

I am a pv advocate and I believe that a
true accounting should incorporate all social and environmental costs, in
addition to the financial ones. However, or perhaps because of that
advocacy, I think that a clear representation needs to made as to the
limitations, as well as the capabilities, of this technology with respect to
people’s energy “needs”.

See below for a more “real
world” projection for what the 3 kW system in question might actually do
in Houston :

Station
Identification

City:

Houston

State:

TX

Latitude:

29.98° N

Longitude:

95.37° W

Elevation:

33 m

PV System
Specifications

DC Rating:

3.0 kW

DC to AC Derate
Factor:

0.770

AC Rating:

2.3 kW

Array Type:

Fixed Tilt

Array Tilt:

30.0°

Array Azimuth:

180.0°

Energy Specifications

Cost of Electricity:

9.2 ¢/kWh

Results

Month

Solar Radiation
(kWh/m2/day)

AC Energy
(kWh)

Energy Value (estimated)
($)

1

3.68

252

23.18

2

4.12

251

23.09

3

4.82

321

29.53

4

4.98

315

28.98

5

5.24

335

30.82

6

5.53

337

31.00

7

5.43

338

31.10

8

5.44

342

31.46

9

5.40

332

30.54

10

5.19

334

30.73

11

4.33

277

25.48

12

3.34

226

20.79

Year

4.79

3660

336.72

And here for an output projection for the
system one might need (with correct array orientation) to hit their 5400
kWh/year consumption mark:

Station Identification

City:

Houston

State:

TX

Latitude:

29.98° N

Longitude:

95.37° W

Elevation:

33 m

PV System Specifications

DC Rating:

4.5 kW

DC to AC Derate Factor:

0.770

AC Rating:

3.5 kW

Array Type:

Fixed Tilt

Array Tilt:

30.0°

Array Azimuth:

180.0°

Energy Specifications

Cost of Electricity:

9.2 ¢/kWh

Results

Month

Solar Radiation
(kWh/m2/day)

AC Energy
(kWh)

Energy Value (estimated)
($)

1

3.68

377

34.68

2

4.12

376

34.59

3

4.82

481

44.25

4

4.98

472

43.42

5

5.24

502

46.18

6

5.53

505

46.46

7

5.43

508

46.74

8

5.44

(Message over 64 KB, truncated)

Robert Johnston

I keep hearing about solar as an insurance policy for power failures. I think a generator would be more reliable. Living on the Gulf Coast (not San Antonio),

Message 4 of 11
, Sep 4, 2005

0 Attachment

I keep hearing about solar as an insurance
policy for power failures. I think a generator would be more reliable. Living
on the Gulf Coast (not San Antonio), I have seen what even Cat I storm winds
can do. I think the chances of any PV panels on or around my home surviving a
hurricane are slim. If the wind didn’t directly send the panels flying,
it would smash them with windblown debri, or drop a tree on them. And I’d
hate to think what flooding would do to electronics.

As an insurance policy against “brownouts”
such as California
experienced a couple years ago, I think it makes more sense. But not for
hurricane insurance.

Why don't we just stop kidding ourselves? The entire
concept of "payback" from a solar power system is a dinosaur from the
1980s when the government, academics and solar vendors alike were trying to
justify to the American consumer (the most uneducated consumer in the
world) why we should invest in solar. At best this data is a weak
marketing tool.

So called calculations of payback are little more than
fiction because all renewable energy systems are subject to the behavior of
weather. We have been trying to predict the weather for thousands of
years with less than accurate results. Because you cannot tell me what
the weather will be like tomorrow you also cannot tell me how much power a
renewable energy power system will produce. I can offer you any
"calculations" you like for a solar power system for any
location in the world.
Your calculations, my calculations and anyone else's calculations would be
just as accurate as gazing into a crystal ball. And your crystal ball
works just as well as mine. Most American consumers don't read and would
not even understand payback calculations and estimates. And let's not
even bring up the topic of efficiencies. When I am asked about efficiency
that is always the first indication of a clueless consumer. The next
indication would be that consumer concerned about the "imbedded
pollution" of the solar manufacturing process. Give me a
break. These concerns and payback concerns are the concerns of a consumer
who probably has no intention of investing in renewable energy - plain and
simple.

The basic practical fact of investing in solar
technology (or any renewable energy technology) is that a solar power system is
an on site electric power generator capable of providing power if no utility
power is available at all, capable of providing electricity in the event
of utility failure and/or capable of producing distributed power that can be
applied back to the grid at large. The fuel for that generator is free,
natural, nonpolluting sunshine. If the American consumer cannot
recognize the logic and practical nature of this basic fact (and they
don't) why waste time producing pages of nearly useless
data that will end up in the trash can? And what about the risk that some
grubby lawyer might use that data against you in the future because your
solar power system did not deliver as predicted by your payback estimates?

There are many ways of calculating the
“payback” of a pv system………some which make it
look more appealing, some which make it worse, some using very basic
calculations, some using complex financial analyses and calculated energy
projections.

The method however, that has been
presented in this thread, is most peculiar.

First of all, while acceptable to use the
NREL average for back-of-the envelope calculations, it probably isn’t
acceptable to simply de- rate
the STC rating of the
array by the inefficiency of it as there are many other inefficiencies that
come into play by the time the power from the system in question gets put to
work.

This pitfall is illuminated in the example
that a 3 kW array will provide the 450 kWh/month (average) or 5400
kWh/year. To be clear: it would not, at least not in
Houston .

Secondly, and regarding the basis for the
calculations we have seen:

It will be very hard to install to
functionality a quality 3 kW system installed for $18K. Furthermore, it
would seem that the example case is assuming a $.56/kWh
rate (5400 kWh/Year for $3K).
Perhaps this includes environmental costs or other “intangibles”,
which is most appropriate in a big-picture way, but maybe not so much for a
bare-bones payback analysis.

I am a pv advocate and I believe that a
true accounting should incorporate all social and environmental costs, in
addition to the financial ones. However, or perhaps because of that
advocacy, I think that a clear representation needs to made as to the
limitations, as well as the capabilities, of this technology with respect to
people’s energy “needs”.

See below for a more “real
world” projection for what the 3 kW system in question might actually do
in Houston :

Station
Identification

City:

Houston

State:

TX

Latitude:

29.98° N

Longitude:

95.37° W

Elevation:

33 m

PV System
Specifications

DC
Rating :

3.0 kW

DC to AC Derate
Factor:

0.770

AC
Rating :

2.3 kW

Array Type:

Fixed Tilt

Array Tilt:

30.0°

Array Azimuth:

180.0°

Energy Specifications

Cost of Electricity:

9.2 ¢/kWh

Results

Month

Solar Radiation
(kWh/m2/day)

AC Energy
(kWh)

Energy Value (estimated)
($)

1

3.68

252

23.18

2

4.12

251

23.09

3

4.82

321

29.53

4

4.98

315

28.98

5

5.24

335

30.82

6

5.53

337

31.00

7

5.43

338

31.10

8

5.44

342

31.46

9

5.40

332

30.54

10

5.19

334

30.73

11

4.33

277

25.48

12

3.34

226

20.79

Year

4.79

3660

336.72

And here for an output projection for the
system one might need (with correct array orientation) to hit their 5400
kWh/year consumption mark:

Steve, I respectfully disagree on several points. You cannot lump all comsumers into one group- there are large numbers of highly educated literate consumers

Message 5 of 11
, Sep 4, 2005

0 Attachment

Steve, I respectfully disagree on several
points.

You cannot lump all comsumers into one group- there
are large numbers of highly educated literate consumers who have
questions about solar and renewable energy products and it is our job to
help educate them as to the benefit of our products. Payback is one area
that need to be explained and can be predicted very reliably. You can do alot to
save energy without spending anything on solar panels. conservation, house
design, and several other techniques are the first thing that should be done
before investing in generation capacity.

Weather, although not predictable, is predictable
year over year within a small degree of error thanks to hundreds of years of
weather data, we know generally how much solar irraditation will hit a specific
area on a yearly basis. True this can change but it will not change that
much over time quickly. You cannot agrue that you don't know that Alaska
will be colder than Houston next winter, this is just common sense and
geometry.

We have found an increased interest in all forms or
renewable energy and are happy to provide case studies, calculations and other
"data" from very reliable sources to help people make informed decisions.
Solar panels can be mounted in such as way as to survive hurricane winds
although flying debris may be a problem. Also in a
disaster a generator may be more robust and powerful, but you must have fuel for
this, a luxury that may not be available. We get fuel from the sky every
day for free.

Man's ability to survive and harness nature through
the use of our biggest tool, our brain, is the reason we don't live in caves
anymore.

The future of renewable energy is bright, I like to
see the glass half full and actively try to fill it up the rest of the
way. Just my personal approach.

Why don't we just stop kidding ourselves?
The entire concept of "payback" from a solar power system is a dinosaur from
the 1980s when the government, academics and solar vendors alike were trying
to justify to the American consumer (the most uneducated consumer in the
world) why we should invest in solar. At best this data is a weak
marketing tool.

So called calculations of payback are little more
than fiction because all renewable energy systems are subject to the behavior
of weather. We have been trying to predict the weather for thousands of
years with less than accurate results. Because you cannot tell me what
the weather will be like tomorrow you also cannot tell me how much power a
renewable energy power system will produce. I can offer you any
"calculations" you like for a solar power system for any location in the
world. Your calculations, my calculations and anyone else's
calculations would be just as accurate as gazing into a crystal ball.
And your crystal ball works just as well as mine. Most American
consumers don't read and would not even understand payback calculations and
estimates. And let's not even bring up the topic of efficiencies.
When I am asked about efficiency that is always the first indication of a
clueless consumer. The next indication would be that consumer concerned
about the "imbedded pollution" of the solar manufacturing process. Give
me a break. These concerns and payback concerns are the concerns of a
consumer who probably has no intention of investing in renewable energy -
plain and simple.

The basic practical fact of investing in
solar technology (or any renewable energy technology) is that a solar power
system is an on site electric power generator capable of providing power if no
utility power is available at all, capable of providing electricity in
the event of utility failure and/or capable of producing distributed power
that can be applied back to the grid at large. The fuel for that
generator is free, natural, nonpolluting sunshine. If the American
consumer cannot recognize the logic and practical nature of this basic fact
(and they don't) why waste time producing pages of nearly useless data
that will end up in the trash can? And what about the risk that some
grubby lawyer might use that data against you in the future because your
solar power system did not deliver as predicted by your payback
estimates?

There are many ways
of calculating the payback of a pv system some which make it look more
appealing, some which make it worse, some using very basic calculations,
some using complex financial analyses and calculated energy
projections.

The method however,
that has been presented in this thread, is most
peculiar.

First of all, while
acceptable to use the NREL average for back-of-the envelope calculations, it
probably isnt acceptable to simply de-rate the STC rating of the array by
the inefficiency of it as there are many other inefficiencies that come into
play by the time the power from the system in question gets put to
work.

This pitfall is
illuminated in the example that a 3 kW array will provide the 450 kWh/month
(average) or 5400 kWh/year. To be clear: it would not, at
least not in
Houston .

Secondly, and
regarding the basis for the calculations we have seen:

It will be very
hard to install to functionality a quality 3 kW system installed for
$18K. Furthermore, it would seem that the example case is assuming a
$.56/kWh rate (5400 kWh/Year for $3K). Perhaps this includes
environmental costs or other intangibles, which is most appropriate in a
big-picture way, but maybe not so much for a bare-bones payback
analysis.

I am a pv advocate
and I believe that a true accounting should incorporate all social and
environmental costs, in addition to the financial ones. However, or
perhaps because of that advocacy, I think that a clear representation
needs to made as to the limitations, as well as the capabilities, of this
technology with respect to peoples energy
needs.

See below for a
more real world projection for what the 3 kW system in question might
actually do in
Houston :

Station
Identification

City:

Houston

State:

TX

Latitude:

29.98°
N

Longitude:

95.37°
W

Elevation:

33
m

PV
System Specifications

DC
Rating:

3.0
kW

DC to
AC Derate Factor:

0.770

AC
Rating:

2.3
kW

Array
Type:

Fixed
Tilt

Array
Tilt:

30.0°

Array
Azimuth:

180.0°

Energy
Specifications

Cost of
Electricity:

9.2
¢/kWh

Results

Month

Solar
Radiation(kWh/m2/day)

AC
Energy(kWh)

Energy
Value (estimated)($)

1

3.68

252

23.18

2

4.12

251

23.09

3

4.82

321

29.53

4

4.98

315

28.98

5

5.24

335

30.82

6

5.53

337

31.00

7

5.43

338

31.10

8

5.44

342

31.46

9

5.40

332

30.54

10

5.19

334

30.73

11

4.33

277

25.48

12

3.34

226

20.79

Year

4.79

3660

336.72

And here for an
output projection for the system one might need (with correct array
orientation) to hit their 5400 kWh/year consumption
mark:

[NL]Summary:
The Texas property tax code allows an exemption of the amount of the appraised property value that arises from the installation or construction of a solar or wind-powered energy device that is primarily for the production and distribution of energy for on-site use. [NL][NL]"Solar energy device" means an apparatus designed or adapted to convert the radiant energy from the sun, including energy imparted to plants through photosynthesis employing the bioconversion processes of anaerobic digestion, gasification, pyrolysis, or fermentation, but not including direct combustion, into thermal, mechanical, or electrical energy; to store the converted energy, either in the form to which originally converted or another form; or to distribute radiant solar energy or the energy to which the radiant solar energy is converted. [NL][NL]"Wind-powered energy device" means an apparatus designed or adapted to convert the energy available in the wind into thermal, mechanical, or electrical energy; to store the converted energy, either in the form to which originally converted or another form; or to distribute the converted energy.

TEXAS STATUTES
TITLE 1. PROPERTY TAX CODE
SUBTITLE C. TAXABLE PROPERTY AND EXEMPTIONS
CHAPTER 11. TAXABLE PROPERTY AND EXEMPTIONS
SUBCHAPTER A. TAXABLE PROPERTY
§ 11.27. Solar and Wind-Powered Energy Devices.
(a) A person is entitled to an exemption from taxation of the amount of appraised value of his property that arises from the installation or construction of a solar or wind-powered energy device that is primarily for production and distribution of energy for on-site use.
(b) The comptroller, with the assistance of the Texas Energy and Natural Resources Advisory Council, or its successor, shall develop guidelines to assist local officials in the administration of this section.
(c) In this section:
(1) "Solar energy device" means an apparatus designed or adapted to convert the radiant energy from the sun, including energy imparted to plants through photosynthesis employing the
bioconversion processes of anaerobic digestion, gasification, pyrolysis, or fermentation, but not including direct combustion, into thermal, mechanical, or electrical energy; to store the converted energy, either in the form to which originally converted or another form; or to distribute radiant solar energy or the
energy to which the radiant solar energy is converted.
(2) "Wind-powered energy device" means an apparatus designed or adapted to convert the energy available in the wind into thermal, mechanical, or electrical energy; to store the converted
energy, either in the form to which originally converted or another form; or to distribute the converted energy.

<< File: ATT00012.htm >> Thanks for the help Bashir, your calculations helped me clarify the calcuation process and thanks for the clarification Andrew. I appreciate this thread as it goes to the heart of what we often encounter in the solar business. People want to know how long it will take to pay for their system and it often shows a long time, over 20 years. I have struggled with this and asked Bashir for his method thinking that I had missed something. What is true payback period and what is true cost of line power are legitimate questions.

I do know that new panels are hot or produce up to 15% more than they are rated to allow for some loss in power over time. a 150 watt panel will actually put out over 170 watts. This should be figured into the equation but a dissipation of this effect will need to be included as well.

Incentives are what is driving the market, california being one instance, as well as remote users who have little other choice. For people in urban areas, the payback may be long but seeing what has happened in LA/MS it makes sense to have some solar capability for back-up to run your refrig, phone, some lights and fans in case power goes out. This can be done for $5000 or less and will provide for some security and peace of mind.

Payback goes out the window when the power is out.
solar thermal makes sense right now, payback is less than 5 years.

There are many ways of calculating the "payback" of a pv system...some which make it look more appealing, some which make it worse, some using very basic calculations, some using complex financial analyses and calculated energy projections.

The method however, that has been presented in this thread, is most peculiar.

First of all, while acceptable to use the NREL average for back-of-the envelope calculations, it probably isn't acceptable to simply de-rate the STC rating of the array by the inefficiency of it as there are many other inefficiencies that come into play by the time the power from the system in question gets put to work.

This pitfall is illuminated in the example that a 3 kW array will provide the 450 kWh/month (average) or 5400 kWh/year. To be clear: it would not, at least not in Houston.

Secondly, and regarding the basis for the calculations we have seen:

It will be very hard to install to functionality a quality 3 kW system installed for $18K. Furthermore, it would seem that the example case is assuming a $.56/kWh rate (5400 kWh/Year for $3K). Perhaps this includes environmental costs or other "intangibles", which is most appropriate in a big-picture way, but maybe not so much for a bare-bones payback analysis.

I am a pv advocate and I believe that a true accounting should incorporate all social and environmental costs, in addition to the financial ones. However, or perhaps because of that advocacy, I think that a clear representation needs to made as to the limitations, as well as the capabilities, of this technology with respect to people's energy "needs".

See below for a more "real world" projection for what the 3 kW system in question might actually do in Houston:

Richard, Not much, but at least it doesn t hurt. Tax code specialists please weigh in to correct if need be, but I ve long understood this to simply mean that

Message 7 of 11
, Sep 10, 2005

0 Attachment

Richard,

Not much, but at least it doesn't hurt.

Tax code specialists please weigh in to correct if need be, but I've long
understood this to simply mean that the appraisal valuation is not allowed
to increase because of the installation of one of the described
systems......... and not that there is some sort of deduction or other tax
benefit to that installation.

Summary:
The Texas property tax code allows an exemption of
the amount of the appraised property value that arises from the installation
or construction of a solar or wind-powered energy device that is primarily
for the production and distribution of energy for on-site use.

"Solar energy device" means an apparatus designed or adapted
to convert the radiant energy from the sun, including energy imparted to
plants through photosynthesis employing the bioconversion processes of
anaerobic digestion, gasification, pyrolysis, or fermentation, but not
including direct combustion, into thermal, mechanical, or electrical energy;
to store the converted energy, either in the form to which originally
converted or another form; or to distribute radiant solar energy or the
energy to which the radiant solar energy is converted.

"Wind-powered energy device" means an apparatus designed or
adapted to convert the energy available in the wind into thermal,
mechanical, or electrical energy; to store the converted energy, either in
the form to which originally converted or another form; or to distribute the
converted energy.

TEXAS STATUTES
TITLE 1. PROPERTY TAX CODE
SUBTITLE C. TAXABLE PROPERTY AND EXEMPTIONS
CHAPTER 11. TAXABLE PROPERTY AND EXEMPTIONS
SUBCHAPTER A. TAXABLE PROPERTY
§ 11.27. Solar and Wind-Powered Energy Devices.
(a) A person is entitled to an exemption from taxation of the amount of
appraised value of his property that arises from the installation or
construction of a solar or wind-powered energy device that is primarily for
production and distribution of energy for on-site use.
(b) The comptroller, with the assistance of the Texas Energy and Natural
Resources Advisory Council, or its successor, shall develop guidelines to
assist local officials in the administration of this section.
(c) In this section:
(1) "Solar energy device" means an apparatus designed or adapted to convert
the radiant energy from the sun, including energy imparted to plants through
photosynthesis employing the
bioconversion processes of anaerobic digestion, gasification, pyrolysis, or
fermentation, but not including direct combustion, into thermal, mechanical,
or electrical energy; to store the converted energy, either in the form to
which originally converted or another form; or to distribute radiant solar
energy or the
energy to which the radiant solar energy is converted.
(2) "Wind-powered energy device" means an apparatus designed or adapted to
convert the energy available in the wind into thermal, mechanical, or
electrical energy; to store the converted
energy, either in the form to which originally converted or another form; or
to distribute the converted energy.

<< File: ATT00012.htm >> Thanks for the
help Bashir, your calculations helped me clarify the calcuation process and
thanks for the clarification Andrew. I appreciate this thread as it goes to
the heart of what we often encounter in the solar business. People want to
know how long it will take to pay for their system and it often shows a
long time, over 20 years. I have struggled with this and asked Bashir for
his method thinking that I had missed something. What is true payback
period and what is true cost of line power are legitimate questions.

I do know that new panels are hot or produce
up to 15% more than they are rated to allow for some loss in power over
time. a 150 watt panel will actually put out over 170 watts. This should
be figured into the equation but a dissipation of this effect will need to
be included as well.

Incentives are what is driving the market,
california being one instance, as well as remote users who have little other
choice. For people in urban areas, the payback may be long but seeing what
has happened in LA/MS it makes sense to have some solar capability for
back-up to run your refrig, phone, some lights and fans in case power goes
out. This can be done for $5000 or less and will provide for some security
and peace of mind.

Payback goes out the window when the power
is out.
solar thermal makes sense right now, payback
is less than 5 years.

There are many ways of calculating the
"payback" of a pv system...some which make it look more appealing, some
which make it worse, some using very basic calculations, some using complex
financial analyses and calculated energy projections.

The method however, that has been
presented in this thread, is most peculiar.

First of all, while acceptable to use the
NREL average for back-of-the envelope calculations, it probably isn't
acceptable to simply de-rate the STC rating of the array by the inefficiency
of it as there are many other inefficiencies that come into play by the time
the power from the system in question gets put to work.

This pitfall is illuminated in the example
that a 3 kW array will provide the 450 kWh/month (average) or 5400 kWh/year.
To be clear: it would not, at least not in Houston.

Secondly, and regarding the basis for the
calculations we have seen:

It will be very hard to install to
functionality a quality 3 kW system installed for $18K. Furthermore, it
would seem that the example case is assuming a $.56/kWh rate (5400 kWh/Year
for $3K). Perhaps this includes environmental costs or other "intangibles",
which is most appropriate in a big-picture way, but maybe not so much for a
bare-bones payback analysis.

I am a pv advocate and I believe that a
true accounting should incorporate all social and environmental costs, in
addition to the financial ones. However, or perhaps because of that
advocacy, I think that a clear representation needs to made as to the
limitations, as well as the capabilities, of this technology with respect to
people's energy "needs".

See below for a more "real world"
projection for what the 3 kW system in question might actually do in
Houston: